This invention relates to door lock apparatus, and particularly to the mounting of the door strike for a deadbolt security lock.
The door frame and jamb assemblies of residential dwellings and some commerical buildings are typically constructed of wood, often soft wood such as pine. Such assemblies have proven to be susceptible to unauthorized entry by component failure of the jamb/strike components. Such failure is defined in the ANSI/ASTM F476-76 TEST STANDARD as a pull-out or fracture of the strike attachment screws or any splitting, bending, or fracture of the door jamb at the strike that permits the door to be opened. Typically a metal strike plate is mounted with screws to the jamb portion of the door frame. This strike plate receives the deadbolt when the latter is thrown to the extended lock position. Because such strike plates are typically attached with only two screws, while the door hinges on the opposite edge of the door are mounted with at least six to nine screws, this edge of the door frame on which the lock is mounted is the weaker side. In the typical installation, if an intruder applies a moderate amount of force to such hardward, as with a pry bar, cracks propagate in the wood door frame and/or jamb, and/or the screws bend, any or all of which allow such screws to fall out, to release the door.
This problem is compounded by the fact that the door frame itself may be constructed from relatively thin wood which is inserted into support framing and nailed thereto. This design creates two additional problems. First, there is usually a space left between the support framing and the door frame. When screws are inserted through the door frame therefor, they must extend through this open space before hopefully engaging support framing. Sometimes they do not reach the support framing. Second, even if the screws are long enough to reach the support framing, the space left between the door frame and the support framing creates the possibility that the door frame can be split and the screws readily bent when an intruder applies prying force to the locked door. In this latter situation, the screws can bend even while their inner ends are firmly screwed into the support framing, permitting an intruder to obtain entry into the locked dwelling. Therefore, there is a need for door strike devices which can more effectively secure door security hardware.